Replace crond with a while loop.

Adding the cron command to  /var/spool/cron/crontabs/www-data assumes
that cron, and by extension the nextcloud app, is run as 'www-data'.

'crond' cannot be used with:
exec "echo \"*/%%CRONTAB_INT%% * * * * php -f /var/www/html/cron.php\" | crontab - && crond -f -l 0 -L /dev/stdout"
because that assumes the uid used matches a entry in '/etc/passwd'.

Signed-off-by: Roland Vet <vet.roland@gmail.com>

docker-cron.sh

@@ -1,4 +1,7 @@
 #!/bin/sh
 set -eu
 
-exec busybox crond -f -l 0 -L /dev/stdout
+while [ 1 ]; do
+    (php -f /var/www/html/cron.php &);
+    sleep %%CRONTAB_INT%%m;
+done